This proposal represents a request to support participation in the Pediatric Oncology Group (POG). This cooperative research is devoted to the investigation of chemotherapeutic approaches to acute leukemia and other neoplastic diseases of childhood. Significant palliation and prolongation of survival has been achieved and contributions have been made in clinical pharmacology. However, the real objective of these studies is the eradication of neoplastic diseases by treatment. Studies are being designed to reflect an increasing intensity of attack on the neoplastic cell. The cooperative group technique permits prompt evaluation in series of reasonable size of promising leads in chemotherapy. These leads or new approaches are often suggested by the results of the group's own work in clinical oncology. Thus, a completed protocol often suggests the new avenues to be explored in new protocols. In addition, protocols are designed to exploit maximal clinical or conceptual advances made in experimental animals and/or clinical pilot studies. The Division of Pediatric Hematology-Oncology in the Department of Pediatrics at the University of California, San Diego (UCSD) has a 10 year history of involvement in cooperative group studies with Cancer and Leukemia Group B prior to joining forces with the Pediatric Oncology Group in 1980. During the past 18 months, we have entered 138 patients on 30 protocols: 63 patients on treatment protocols and 45 patients on registries or non-therapeutic ancillary studies. In addition, we have been involved in Group committee work and the design of new Group protocol studies. We plan to continue our active participation in all phases of POG activities.